The present disclosure generally relates to child seat anchor assemblies, and more particularly to child seat anchor assemblies including tunable force, energy absorbing mechanisms.
Child safety seats have traditionally been secured to motor vehicle passenger seats using an existing seat belt. These seat belts, which are anchored to a fixed structural member of the vehicle at each end, are typically threaded through apertures or slots in the child safety seat before being fastened. This process can be somewhat laborious.
More recently, vehicles are being manufactured with features that improve the ease of securing a child seat to the rear seats of the vehicle. For example, vehicles may include fixed rigid anchors to which restraints that are included on a child seat may be engaged. A child safety seat can be engaged with two lower anchors and an upper anchor. The lower anchors are frequently located in the vehicle seat bight or crack or in an opening in a seat cushion; while the upper anchor is generally located behind the vehicle seat, usually on a rearward shelf or on the floor of a cargo area for those motor vehicles not including a rearward shelf, such as utility vehicles, vans, minivans, station wagons, convertibles, aircraft, buses, trucks, and the like. The anchors are generally metallic and have a U- or C-shaped configuration functioning as a receiving portion for the child seat restraints.
Some child safety seats will be equipped with two lower restraints and most forward-facing child seats will include a top restraint. The restraints may be flexible (e.g., a strap or tether with a hook on the end) or rigid (e.g., an inflexible, firm bar with a latch on the end). The occupant of the child seat is secured to the child seat by a seat belt or other securing harness provided by the child seat.
In the event of a rapid deceleration of the vehicle, such as in an impact event, the child seat and occupant tend to continue moving forward, owing to their inertia, until acted on by tension forces in the child seat restraints. Since the anchors to which the child seat restraints are engaged are rigid mechanical devices, the child seat and occupant, from that point on, tend to experience the same deceleration pulse as the vehicle.
To minimize the effects of the force felt and deceleration experienced by the occupant of the child seat, some child seats are equipped with a force limiting energy absorbing mechanism, such as a tear seam in a tether or strap. Alternatively, some anchors are provided with a force limiting energy absorbing mechanism such as a portion that deforms above a selected stress threshold. These types of energy absorbing mechanisms are irreversible for single use. Once they have been triggered, they must be replaced. More importantly, these energy absorbing mechanisms tend to be operable only at a fixed or non-tunable level of force.
Thus, despite their suitability for their intended purposes, there nonetheless remains a need in the art for improved devices for minimizing the mass dependent deceleration levels experienced by a child seat occupant. It would be particularly advantageous if the response of these devices were tunable, especially in light of the fact that there is great variability in child seat occupant masses and in rates of deceleration. It would also be advantageous if these devices were reversible (i.e., they could be triggered more than once without necessitating complete replacement).